Does anyone on here know anyone associated with the former Horizon Instruments Company? Or someone who might?
They apparently ceased business in February 2021. But the FAA still has them recorded as holding the STC for the P1000. I have one in my plane but lack the “Assignment letter” to make it a “legal” installation.
The ACO in LA says I need to contact whoever legally holds the STC.
I have looked up the former senior folks but none come up with active contact info.

Anybody?

I have had some issues with their tachs and have not been able to get a hold of them for repair work. Been trying for a couple of years amd have never had a reply or email for the many messages I left/sent. I won't install another for any customers and wouldn't recommend them due to the lack of customer support.

I wanted to put a new to me p-1000 in my plane. I did get ahold of the company and was told they would not reassign the stc or paperwork from one plane to the next, "out of the question".

They were what one would call "hard to deal with". Went with the EI tac and never looked back.